Definition: Geometric ownership and footprints

Mutable geometric cells comprise capacity cells and identified link cells. Their permissions are linearly owned. An endpoint region is not, by itself, a permission to modify every incident link.

A transition has a write footprint $W$, a read footprint $D$, and a guard. Its output on $W$ depends only on data in $D\cup W$, and it fixes all cells outside $W$.

Two transitions are independent if

and each guard remains true after the other transition.